The present invention relates to a brake, in particular a drum brake.
Drum brakes are known where a leading brake shoe and a trailing brake shoe are mounted on a brake support. The brake shoes are arcuate. The leading brake shoe is mounted on the brake support via a pivot, and the training brake shoe is mounted on the brake support via a pivot. At the end of the brake shoes remote from the pivots there is an “S” cam mounted on an actuation shaft. One leg of the S-cam engages the leading brake shoe, typically via a roller, and the other leg of the S-cam engages the trailing brake shoe, typically via a roller. Rotation of the actuation shaft causes the S-cam to move the rollers of the leading and trailing brake shoes apart, thereby engaging the friction surface of the leading and trailing brake shoes with the brake drum, thereby braking the brake drum.
On commercial vehicles, an end of the actuation shaft remote from the S-cam includes a lever, operated by an actuator, typically an air actuator. The air actuator and the lever are relatively bulky, and therefore space needs to be provided for these components.
The shaft axis is always parallel to the axis of rotation of the wheel (which is coincident with the axis of rotation of the brake drum). As such, the circumferential and radial positioning of the S-cam necessarily determines the circumferential and radial positioning of the end of the actuation shaft remote from the S-cam (since the shaft axis lies parallel to the wheel axis). Thus, freedom of design choice is limited in respect of known brakes.
An object of the present invention is to provide a brake which can more readily be designed for a vehicle wherein the space limitations for various components of the brake are limited.